1. Field of the Invention
The present invention relates to a packing for liquid chromatography, and a process for producing the same. In particular, the present invention relates to a microspherical packing for liquid chromatography, which comprises a porous silicon carbide having numerous through-pores, and a process for producing the same.
2. Prior Art
Packings or adsorbents used hitherto for liquid chromatography include those based on a silica gel such as ODS silica gel and those based on synthetic resins.
Such silica gel-based packings are superior in that they have relatively high mechanical strength and high separation power. In addition, since they undergo only slight swelling or shrinkage in various organic solvents, they can easily be changed in use for analysis conditions with different eluents. However, they have defects that they are poor in chemical resistance in alkaline and acidic regions and are also poor in thermal resistance.
On the other hand, although such synthetic resin-based packings have high chemical resistance, they are defective in that they have low mechanical strength and they are swollen or shrunk in a solvent due to their low solvent resistance thereby to make it difficult for them to change in use for analysis conditions with different eluents.
Carbonaceous packings are also known as packings for conventional liquid chromatography. The carbonaceous packings are chemically stable and have high mechanical strength and such features that ODS silica gel and the like do not possess, since the carbonaceous packings are covered on their whole surface with .pi.-electrons. However, the carbonaceous packings have strong power of adsorbing particularly polycyclic aromatic compounds since they are covered with .pi.-electrons as described above, and, therefore, they have defects that they will cause an elution time to be prolonged too much depending on samples used to be chromatographed, will cause remarkable tailing to occur, or will cause the elution to become impossible.